Enhancement of Magnetic Flux Transferred to the Magnetotail Due to a Storm‐Time Kelvin‐Helmholtz Instability

Abstract Along the flank magnetopause, magnetosheath flow interfaced with the relatively stationary magnetosphere produces strong flow shears, and the Kelvin‐Helmholtz instability (KHI) occurs. When the interplanetary magnetic field (IMF) is southward, anti‐parallel day‐side reconnection and KHI can interact, which may enhance the reconnection rate as KHI compresses the current layer and increases the length of the x‐line. If this reconnection transports sufficient magnetic flux into the magnetotail, it may disrupt the magnetotail current sheet. This study examines a Multiscale Atmosphere Geospace Environment (MAGE) simulation of the 10–11 October 2024 geomagnetic storm to quantify the contribution of magnetic flux transported into the magnetotail that is generated where KHI and the anti‐parallel x‐line are co‐located. During a 15‐min interval, the KH unstable dawn flank magnetopause reconnects ∼13% of the flux added to the northern lobe from the subsolar region, or ∼5% of the total magnetospheric open flux.